A thick peat riverbed can seal a river off from an underlying aquifer.

Evidence

As far as Pinder was concerned, this and similar measurements from other monitoring wells proved beyond a doubt that groundwater from Beatrice was drawn under the river and into the city wells. It also proved that the Aberjona River played almost no role in satisfying the demand of the wells for water. Pinder reasoned that the thick layer of peat that formed the riverbed—twenty or more feet of decomposed leaves, roots, and branches—acted as a nearly impermeable lining. The river, in other words, was not a barrier. It wasn’t even relevant. — , Harr Jonathan - A Civil Action, 1996

Categorization

• XREF: Connects to the earlier note about natural filters and linings — peat as an impermeable membrane is a concrete example of a streambed shaping what moves between surface and groundwater. — connects to: Groundwater-fed rivers can lose water to wells during pumping. — , Harr Jonathan - A Civil Action , 2046